1. Field of the Invention
The present invention relates to a contactless communication circuit that transmits/receives signals through, e.g., so-called contactless communication, and a portable terminal having its contactless communication function.
2. Description of Related Art
Recently, contactless IC cards (hereinafter referred to as “RFID card(s)”) incorporating an RFID (Radio Frequency-IDentification) circuit therein are gaining popularity as transportation tickets, prepaid cards and the like, thanks to their advantages, such as excellent usability, durability and maintainability, as well as simultaneous-access-to-multiple-cards capability.
Additionally, a portable telephone terminal incorporating such an RFID card has been marketed lately. By electronically transmitting/receiving money information between the RFID card incorporated in the portable telephone terminal and a contactless IC card reader/writer (hereinafter referred to as “RFID reader/writer”) installed at, e.g., an automatic ticket gate or a checkout in a shop, a user can pay for a ticket or for a purchase at the shop, for example.
Furthermore, Published Japanese Patent Application No. 2004-307032 discloses a compact, lightweight portable terminal, which is a contactless RFID reader/writer type portable terminal, in which two or all of an antenna of the contactless RFID reader/writer, an antenna for communication with a host computer, and a coil for contactless recharging are jointly used, to make the portable terminal compact and lightweight.